The four-star commander of U.S. Pacific Command says the era when the U.S. military enjoys uncontested control over the Pacific’s blue water and its airspace is coming to an end.

Adm. Sam Locklear told a Navy conference in Virginia that the rise of China is a key factor that is putting at risk U.S. Navy ships and service members in the Pacific.

“Our historic dominance that most of us in this room have enjoyed is diminishing, no question,” Locklear said at the Surface Navy Association’s annual meeting near the Pentagon.

“We need to think about all scenarios, not just the ones we’ve been dealing with over the last several years where we’ve enjoyed basic air superiority and basic sea superiority. There are places in the world where in this century we won’t have them,” Locklear said.

Locklear rattled off a string of reasons for the military’s 2012 shift in strategy that calls for a “pivot to Asia.”

For one thing, the region “from Hollywood to Bollywood” is “the economic engine that drives the global economy,” he said.

The region also is becoming increasingly militarized and has no NATO-like security structure to prevent conflicts. And the rise of China’s military spending and capability is upending the status quo that took root after World War II.

Locklear said the focus on the Middle East over the past couple decades has drawn some attention from the military’s needs in the Pacific and its offensive capabilities at sea.

“To be honest with you, the lack of urgency on the development next-generation, surface-launch, over the horizon cruise missile is troubling,” Locklear said. “As the PACOM commander, I need you to be thinking in the offensive: How are you going to show up? How are you going to be dominant? How are you going to be lethal?”

It remains unclear what impact China ultimately will have on the U.S role in the Pacific.

“China is going to rise, we all know that. [But] how are they behaving? That is really the question,” Locklear said. “The PACOM goal is for China to be a net provider of security, not a net user of security.”

Reminders of Chinese military growth are now routine in the Pacific. The Navy recently acknowledged that a U.S. ship narrowly averted a collision with a Chinese ship that was conducting an exercise in international waters.

The Pentagon also acknowledged that the Chinese tested a hypersonic strike vehicle that could penetrate the current U.S. missile defense system.

“In the end, the bottom-line problem here is that ... we operate freely in international waters — period,” he said.

Locklear noted that the Chinese will for the first time this year join the annual naval exercise with the U.S. and its Pacific allies, an important step in developing stronger ties with the Chinese navy.

Beyond China, Locklear said his most urgent concern is “an unpredictable North Korea,” its nuclear program and the missile development that is extending the reach of those nuclear weapons.

Today, North Korea has the capability to trigger a “catastrophic event” in the form of a nuclear assault on South Korea, which would severely impact the world economy and long-term security in Asia, Locklear said.

“The ‘flash to bang’ of what can happen to Korea is very short,” Locklear said.